Blackboard supporting structure



Sept- 15 1953 l.. F. URBAIN 2,651,852

BLCKBOARDv SUPPORTING STRUCTURE Filed Aug. 17, 1949 5 Sheets-Sheet lSept. 15, 1953 L. F. URBAIN BLAcxBoARD SUPPORTING STRUCTURE VENTOR. M

5 Sheets-Sheet 2 Filed Aug. 17. 1949 5 Sheets-Sheet 3 m MJ Sept. 15,1953 L. F. URBAIN- BLACKBOARD SUPPORTING STRUCTURE 17 1949 2Q-ff FiledAug.

Sept. 15, 1953 L. F. URBAIN BLAcKBoARD SUPPORTING STRUCTURE Filed Aug.17 1949 5 sheets-sheet 4 I Sept. 15, 1953 L. F. URBAIN 2,651,852

BLACKBOARD SUPPORTING STRUCTURE Filed Aug. l?, 1949 5 Sheets-Sheet 5 INVEN TOR.

@0MM/m B Y m @www Patented Sept. 15, 1953 UNITED STATES PATENT OFFICE 14Claims.

The present invention relates to a display board construction andparticularly to a structure for mounting display boards, blackboards andthe like on a wall.

The present invention contempla-tes providing structure for mountingdisplay boards, blackboards and the like. Such mounting is oftenaccomplished by providing a series of contact points of plaster or thelike in back of the blackboard element and then applying a retainingtrim. Various gripping means have been used to enga-ge the periphery ofeach blackboard slab and secure it in piace. In most priorYconstructions the slabs have been clamped between the trim and the rigidbacking structure, which even under ideal conditions tends to keep theblackboard slabs continually stressed unless extreme care is taken inthe mounting operation. Due to the fact that blackboard slabs,particularly those of slate, are often not of uniform thickness, theconditions are seldom ideal `and the slabs are constantly stressedregardless of the care taken in mounting them.

An important object of the present invention is to overcome theforegoing and other difficulties by providing an improved mountingstructure for holding blackboard slabs or the like in floating positionunder resilient pressure.

For the most permanent blackboard mounting possible, it is desirable tobuild the blackboard into the wall so that the blackboard slab is flushwith the plaster of the wall and only the trim eX- tends outwardlytherefrom. While this is desirable, it is not always feasible, as inorder to keep costs down, unfinished or semi-finished Walls are oftenused, such as concrete, tile or cast cinder block. With suchconstruction, it is of course impossible to mount the blackboard in awall recess, and the blackboard is accordingly mounted on the surface ofwall. At other times a blackboard or other display board may be mountedon a wall where it was not planned to be when the building was designed,and it is not practical to chip away the plaster or other wall finish.

An important object of this invention is to provide an improved andattractive structure for' mounting a blackboard or the like on thesurface of any wall available.

Another object of this invention is to provide a simplified ground forthe mounting of a blackboard or the like.

Yet another object of this invention vis to provide an improvedblackboard mounting structure including an improved clip for mountingtrim and chalk troughs with no fastenings visible,

the clip cooperating with the improved ground so as to be mountable onlyin correct position and yet usable with any type of wooden ground.

A still further object of this invention resides in the provision of anornamental trim for a blackboard or the like which has a projectingportion to overlie and cover the grounds.

Yet another object of this invention is to provide a chalk trough havinga portion overlying and covering the lower ground.

Another object of this invention is the provision of a recessed chalktrough, the recess facilitating mounting and adding to the feather edgecontact of the chalk trough against the blackboard to preclude thepassage of chalk dust therebetween.

A still further object of this invention is the provision of a shelftype chalk trough which is attractive in appearance, easy to mount andinexpensive to manufacture.

Other and further objects and advantages of the present invention willbe apparent from la perusal of the following description when taken inconjunction with the accompanying drawings in which:

Fig. 1 is a perspective view of a surface applied blackboard or the likeshowing a single panel construction;

Fig. 2 is a view similar to Fig. l showing a blackboard in conjunctionwith tack boards and a map rail;

Figure 3 is a View similar to Figure 1 in which the board is comprisedof two panels and has a divider rail between them;

Figure 4 is an enlarged perspective View partly in section taken alongthe line 4 4 in Figure 3;

Figure 5 is a perspective View of a map rail supporting a map hook andpaper clip;

Figure 6 is a view similar to Figure 5 showing a combination map railand tack board;

Figure 7 is a perspective view partly in section of an inclined closedtype chalk trough;

Figure 8 is a perspective view of an end plate for a shelf type chalktrough;

Figure 9 is a sectional view of a shelf type chalk trough with the endplate in place;

Figure 10 is a perspective view of my improved mounting clip;

Figure 11 is a sectional View taken along the line lI-Il in Figure 7;

Figure 12 is a sectional View similar to Figure 4 showing a recessedblackboard construction;

Figure 13 is a perspective view of a map rail;

Figure 14 is a sectional View taken along the line i4-I4 in Figure 13;

Figure is a perspective sectional view showing a chalk trough with therecessed type of construction;

Figure 16 is a perspective view showing the end plate for an inclinedtype chalk trough;

Figure 17 is a View taken along the line I'I--ll in Fig. 16;

Figure 18 is a front elevational view showing the foundation of groundsfor a surface applied type of blackboard;

Figure 19 is a detailed perspective view of a portion of the lowerground rail shown in Figure 18;

Figure 20 is an enlarged perspectiveview of the mounting blocks shown inFigure 18;

Figure 21 is a sectional View of a modified type of chalk trough;

Figure 22 is a view similar .to Figure 4 showing a surface appliedblackboard mounting construction using wooden grounds for a foundation;

Figure 23 is a s ectional View of a map rail with wooden groundconstruction;

Figure 24 is a perspective view showing the arrangement of woodengrounds as applied to blackboardconstruction; and

Figures 25 and 26 are detailed sectional views showing supporting clipsas applied to wooden grounds.

Where I refer 4to a blackboard throughout the ensuing description, it isto be understood that I have in mindany type of chalkboard such asslate, wood, glass,7 or composition, and oi any desirable color, andthat I also have in mind any other typeof display board such as abulletin board vof Vcork or composition.

In Figure 1 is shown my improved type of sur face applied blackboardshowing single panel construction. AThis blackboard includes a singlepanel or slab 36 of slate vor other type of blackboard, mounting trim 32and a chalk trough 34, all of which, are mounted on the exterior surfaceof any wall 36, A similar construction is shown in Figure in which vtheblackboard consists of two panels or slabs a and 30D as well asornamental supporting trim 32 and a chalk rail 34. This Constructionadditionally includes a niullion or divider strip 3l between theupperand lower blackboard SlateS. Figure 2 shows ablackboard constructioncomprising a single Aslab 3 6 of chalk board as well as horizontal andvertical tack boards 38 and 40 respectively. Ornamental trim 32surrounds the external periphery of the structure 'exceptv for the loweredge Where a chalk trough or rail 34 is located. A map rail v42, whichwill be referred to later in greater detail, separates the horizontaltack board 38 from the chalk board 30 and from the vertical tack board40. The chalk board and verticaltackboard farese'parated by a dividerstrip or mullion'44. Thebasic structure of each of these blackboardconstructions is revealed in Figure 4 which 'is a lperspective sectionalView of the construction shown in Figure 3. p

The foundation of the blackboard mounting structure includes a pluralityof horizontal grounds 46, '48. and v5'() and a pair of vertical grounds52 and lid'which are best seen v in Figure 18. Again referring to Figure4, andadditionally to Figure 19, each of the grounds 46, 50, 52 and 54which lie around the outside of the structure comprises an essentiallychannel-shaped body portion 56 including a front face supplied with alongitudinal recess 58 which will be referred'to later in greaterparticularity. A short inturned flange 6E) along one edge of the bodyvpor-tion provides longitudinal rigidity. An outwardly directed flange62 along the other longitudinal edge of the body portion 56 also impartslongitudinal rigidity and supplies a mounting surface for mountingsprings 64. Each of the mounting springs, as may be seen in Figure 19,comprises a flat central body portion 66 with outwardly extending wings68 terminated in tips l0 which may be bent slightly backward. Thesprings are centrally apertured and may be secured to the flange 62 ofthe grounds by rivets or screws 12 which may extend through the flangeinto the wall 36 for greater mounting strength. The rec ess 58 in thefront face of each of the grounds is apertured at spaced intervals toreceive mounting members 14 which pass into a wall and may be nails,toggle bolts or screws as the situation demands. In Figure 4 it may beseen that the central ground 48 is similar to the other grounds but hastwo extending flanges 62 to support springs 64 and consequently slabs30a and 3 0b on( each side thereof. In order to support the slabs otherthan peripherally, a plurality of wooden blocks I6 each carrying one ofthe springs E4 as illustrated in detail in Figure 20 are disposed atdesirable intervals behind each slab. The intervals in the presentillustration may be 18 inches. Each of the blocks may be ofsubstantially the same thickness as the grounds 46 through 54- ifdesired although this is not essential as the mounting springs willcompensate for a great diiference in thickness. Each of the mountingsprings 64 may be secured by lmeans such as a screw T8, and the blocksmay be secured to the wall by means such as nails 60 or an adhesive suchas the type `known as mastic. It may be readily seen that eachAblackboard slab is supported in floating position 'by the plurality ofresilient springs 64 and by the body portions of one of the grounds 46,48.

The blackboard slabs are held in position against the resilient springs64 by means of clips 82, one of which is illustrated in perspective inFigure 10. Each clip comprises a body portion 84, which is substantiallyflat. Transverse vertical ridges 86 are stamped in the body portion to-provide rigidity, and mounting vapertures 88, which are preferablythree in number, are provided in this body portion. The top edge of thebody portion is bent to form a longitudinal shoulder 90 and a flange 92extending therefrom at an acute angle relative to theplane of the bodyportion. The lower longitudinal edge of the body portion is alsoprovided with a longitudinal shoulder 94 and a substantially U-Shapedchannel providing a camming surface 96. Lugs 98 are struck outrearwardly from the -ends of the body portion 84 at substantially rightangles thereto for cooperation with the recess 58 of each of the groundsso that it is impossible to mount the clip in any position but thecorrect position, or one directly opposite thereto which is readilyobvious, and consequently very ylittle care need be taken in'mountingthe clips. As maybe seen in Figure 4, the edge of the body portionadjacent one or rboth of the shoulders 90, 94 -overlies the edge of theblackboard to clamp the board resiliently against the springs 64. In thecase'of all'of Vthe'clips except those along the bottom'ground-there'islittle force exerted against them and they maybe secured by a vsinglescrew |00 which is preferably of ythe self-tappingtype'andis'screwedintoone of the aperturesin the recess58'which is not occupiedby'a'mounting screw 14. If it ywere'no't'f'or the lugs 98 it would notbe possible to use a single screw as each clip would be prone to rotatevery readily.

If the blackboard or the like were secured in place only by thestructure heretofore described, it would be operable but would not be atall attractive in appearance. To improve the appearance of the structureand to prolong its life by covering all operative parts, I provide theperipheral mounting trim 32 and the mullion trim 31 heretofore noted.Attention is directed first to the mullion trim 3'1, which as may beseen in Figure 4 is symmetrical and is essentially channel-shaped,having inturned flanges 102 at its free edges and an attractive frontface 104, which in the present illustration is scalloped. The mulliontrim may be readily applied by placing one of the flanges 102 over theflange 02 of the clips 82 along the central ground 48 and by thenforcing the other flange 102 inwardly against the camming surface 96 ofthe clips 82. The mullion trim 102 is resilient, preferably being formedof extruded aluminum and consequently is readliy snapped into place overthe camming surface 96 with the flanges 102 abutting the shoulders 90and 94. The peripheral trim 32 applied along the top and sides of theblackboard is similar to the mullion trim, having a channel-shapedportion 106, inturned flanges 102 and an ornamental front surface |04.Additionally, the peripheral trim 32 includes a side wall |08 extendingfrom one of the sides of the channelshaped portion 106 and at rightangles to the flange |02. The side wall terminates in an angled flange110 extending longitudinally therealong. As may be seen in Figure 4, thetrim 32 is applied by placing the flange 102 adjacent the side wall 108over the flange 92 of the clips mounted on the peripheral grounds andforcing the other flange 10,2 over the camming surfaces 96.

The clips on the lower ground in addition to the lower edge of theblackboard support a chalk trough 34 which in Figure 4 is illustrated asbeling of the shelf type. The trough comprises an undulating supportingsurface 112 having a depending longitudinal flange or front wall |14similar to the trim 34. This flange has an ornamental outside surfaceand has an inwardly extending wall 116. A longitudinal flange 118similar to the flange 102 on the trim projects inwardly from the wall 116. The upper surface 112 is curled over along its free edge to providea cylindrical configuration 1 I3 which imparts attractive appearance andconsiderably increases r the strength and rigidity of the chalk trough.At the inner longitudinal extremity the top surface l2 extends upwardlyto form a flat surface forming an angle with the blackboard which may beon the order of The back of the inclined surface 120 is provided with arecess |18 which tapers into the surface 120 at a very sharp angle toprovide a sharp edge 122 of the type generally known as a feather edgeimpinging against the surface of the blackboard. From beneath the recessa flange 123, similar to the flanges 102 of the trim, depends. The chalktrough is mount@ over the clips 82 in the same manner the trirn ismounted-that is by placing the flange 123 over the flanges 92 of theclips and pushing inwardly to force the wall or flange 118 over thecamming surfaces 9B. An end portion may be provided at each end of thechalk rail if desired, and one is illustrated at a later point inconjunction with a modification of the invention. As mayV readly beseen, the feather edge 122 prevents chalk dust from getting between thechalk rail or trough and the blackboard. All of the dust falling downthe surface of the board is directed by the inclined surface to thelower part of the undulations of the upper surface 1 12 from whence itmay be readily swept out one end into a wastebasket or the like. Itshould be noted that an eraser rests on the top portions of theundulations so that it does not collect any dust from the chalk trough.

In the construction shown in Figure 2, a map rail between the horizontaltack board 38 and the blackboard 30 is included. This construction isshown in greater detail in Figure 5 and an alternative form thereof isshown in Figure 6. A ground 124 similar to the two-flanged typeconstituting the mullion ground 08 is provided between the blackboard orchalk board 30 and the horizontal tack board 38. As the tack board 38 isgenerally of some rather soft material such as cork, it is preferable toprovide it with a backing 120 to impart stiffness. The fact that thetack board portion is then thicker than the blackboard portion is of nogreat consequence as the difference is readily taken up by the mountingsprings 66. A longitudinal channel-shaped rail 128 having longitudinalinturned flanges 130 is secured to the ground 124 by means of screws 132which are preferably of the self-tapping type and are threaded intoapertures in the ground. The rail 128 is wider than the body portion ofthe ground 1211, and consequently its edges overlie and secure the tackboard 38 and blackboard 30 against the springs 64. In addition tosecuring the tack board and blackboard, the rail 128 slidably secures aplurality of display fixtures or blocks 134. The longitudinal edges ofthe block may be chamfered as at 136 and 138 and are provided withlongitudinal slots 140 and 142. The side walls of the lower slot 142 aresomewhat shorter than those of the upper slot so that the block |34 maybe interengaged with the rail 128 by placing the upper slot 140 over theupper rail flange lifting the block 134 upward and inward and thenlowering the block with the lower slot 142 over the lower flange 130.The block 134 is provided with a hook 14A extending transversely forcarrying maps and other articles. The hook 144 is threaded into theblock |34 and secured thereto a paper clip 1415 comprising resilientleaf springs 148 and 150 bent toward each other so as to meet near theirextremities and having reversely bent tips to facilitate the placing ofpapers therebetween.

The form of the invention shown in Figure 6 is somewhat similar to thatshown in Figure 5, having a tack board 38 and blackboard 30 Secured onopposite sides of a doubly-flanged ground 124, the tack board 38 againbeing provided with a backing 12B. A rail |52 is secured to the ground124 as by means of self-tapping screws and has its longitudinal edgesoverlying the tack board 38 and blackboard 30 to secure them in positionagainst the mounting springs 64. The rail 152 is comprised of a channelportion 156 having inturned flanges 150 and 160 and a channel portion162 having inturned flanges 164 and |66. A strip of cork 168 or othersuitable material for receiving thumb tacks and the like is securedwithin the lower channel 162 for securing miscellaneous papers, and isof particular use when a second blackboard rather than the tack board 38is provided. A block 110 somewhat similar to the block 134 is securedwithin thezupper channelby having .slots I'l'2iand |114 overlying theflanges |50 and |60. The essential diierence betweenthe Vblock |l'0 andthe block 434 is that the slot |74 is adjacent the mid-portion of theblock rather than ai; the lower .longitudinal edge. The inner lwall ofthe slot v |214 is shortsothat the blockmay be slidably secured in thechannel inthe same m'annerin which the .block i343 .is 'secured in .itslchannel. The block L|l carries .a hook IM and paper clip |46 `which maybe identical with the similarly numberedpartscarried by the block i3d.

`In Figure 7 Ihavesh'own an inclined, closed type-ofchalk .trough .whichis stronger than the shelf type, is=rnore attractive and is .morereadily cleaned. The iblackboard lib, the ground 50. themounting springsAili and the clips'82may all be identical with the similarly numberednparts irl-'Figure 4. The rground may be secured tothe Wall-'30hysimilar fasteningimeans such. as screws 'Hand the clips may be securedto the ground by-a pair of self-tapping screws ellla .placed in the twoextreme apertures of the clip and screwed into apertures in the ground50. The pair of screws is used hereA and in the other chalk'troughmountingsratner than a single screw as in the trim-m'ountingas there isapt to be considerable strain thrown on the clips 82 such as bychildrenleaning Aon the chalk trough. The chalk trough itself has an inclinedundulating upper surface llhavinga feather edge |80 along its upperlongitudinal-.surface whereit is joined by a recess |18. The recess |18like the recess H3 in the shelf type of chalk trough imparts iiexibilityto the upwardly extending portion carrying `the feather edge .andlgreatly facilitates the mounting of thefchalk trough. Beneath the recess|83 a depending flange |82iis provided for cooperation with the flange92 along the top of the clip 82. The surface I1-E at its outer extremityis bent upwardly and then back upon itself to vforrn a cylindrical edgeportion |36 extending-outwardly into asmoothly curved wall |06terminatingin a substantially horizontal Wall or surface |80 abuttingthe wall 36. A narrow, longitudinal wall |90 extends upward from thehorizontal portion |88 to engage the can/lining surface ASiti of theclip, the mounting of the `chalk trough being similar to that of theshelf type trough ||2. In this form of trough, dust falling down theouter surface of the blackboard '30h is prevented Vfrom` sifting betweenthetrough and the board -by-'thefeather edge |80, and consequently allof the dust ends-up in the lowest undulation of the upper surfaceIl'from whence it may-be readily swept out either end into a wastebasketor the -like. An eraser resting in the chalk trough abuts against theinnermost portion 'of the `Acylindrical edge I8@ and consequently doesnotextend downwardly into the chalk dust'and remains clean.

Although the foregoing form of chalk trough is ventirely satisfactory ingeneral, there are'sorneti1n'es"encountered extreme conditions in Awhichit is 'difficult tomove the wall |88 past the camming surface 9E. Inorder to obviate this situation,`l'haveprovided the vform of chalktrough shown in Figure '21. The groundl 50,' clip 82 and clip mountingscrews ia may be identical with those shownV in Figure 7. rEhe chalktrough itself may be identical with that shown in Figure 'I except thatinstead of having a horizontal extending wall iBS I have providedaquartereroun'd section 2 i2 merging into a horizontallyextendinglongitudinal wall Zit which is vertically displaced downwardly from 'thecurved wall J86. In this modica-tion, ysuilicient clearance is Aprovided:between the camming surface 96 and the horizontal wal12|i4 to.accommodate any .eventuality encountered in practice.

Although it is desirable to cover all .of 'the grounds, :it is notnecessary from an 'aesthetic standpoint to .covertthe lower groundalonglthe bottom as this portion .is generally not 'risible anyway.-Inrsuch caselzhaveprovided the .shelf typechalkntrough |.2u shown inFigure 9` which isidentical with `the chalkttrough I: 2 .except .that itlacks .the-extending wall |I16 which :covers .the lower portion of `.the.lower ground. The lower portion thus A.ends with an upturned wallyl'lilia whichucooperates with the camming surface 0E ofa-clippforsecuring purposes. Inconjunction withlthis:chalkvtrough, I haveillustrated an end plate lwhichl is usable .either `with .this troughvor withfthe trough |'l2shownin Figure 4. The. end plate comprisesaaV'side wall |92 from which extend an undulatingtop surface I'Sli similarto the surface? H2 'ofthe'chalk troughand an inclined surface |96similar #to the inclined surface |20. 1Ehe surface IS isof greatertransverseextent thanthe surf-ace |f2`0,'or iafas shown inFigure 9, Isothat it may cover Athe 'side ofthe lower corner of theblaekboard'mounting structure as well as the-end of the chalk trough. `Acylindrical lug i'f extends vin a longitudinalf direction from the endplate and fits within the cylindrical -edge v| |3'a of 'thetrcugirFrom'l theV lower part of the upper surface fiS'Zl extends aniundulatingsurface .i200 which-underlies theftop surface |2 of the chalk trough.A'lug 202 extends longitudinally from a wall 204 similar to the frontsurface ||4a of the trough -and'liesbehin'd `the surface ||4a to lockitIbetween thelu'g and the vsurface2lltl, as may 'be seen in!" Figure 9,it'being. remembered that that subscript-is used on the numbersreferring to the chalk trough as this is a modiiied form. A' lowerwall-'206 v'extends-in a longitudinal direction frorntheendwall |92 tomeet the wall I I6, and a'lug 208 yextending from the wall 206 'overliesthe "top ofthe wall I-'IB and -abuts against that upwardly extending`wall Ivi-8a. The end plate may ice-secured to the kchalk trough Vby a-screw 2 ieXtendingfthrough-the cylindrical` longitudinal edge-I |3a ofthe upper surfacer 12al andvinto the lu'g- |98.

Although vone -of the primary objects of this invention is to present astructure for vmounting a blackboard or the like on the outer surface ofa wall, vthe structure heretofore disclosed Vmay be used with veryrslight Inodication for a sunken or recessed-inounting'in which theblackboard is flush withfthe wall. I have illustrated this modificationin Figure l2, which is similar to Figure -except that the mullionitrim,which is identical, has been'orrultted from the'view. The upper andlower grounds vfili Aand "50' having `mounting springs 64' lmay beidentical with those shown in Figure 4. These grounds may be mounted onthe Vwall 36- in thelsaine manner as `in the previous illustration afterwhichjplaster isapplied to the walltto form an outer wall'2l'6 rwhich isilush with the front surfaces of the grounds. The upper trim '32h aswell as'the trim along the Verticalsidesis similar to the mullion trimpreviously illustrated, and has-'an ornamental frontface |0412 andvinturned anges |0227 whi'chcooperate with the fiange-92 andcannnin'gsurface`96 .onithe mountingclip, 82. It 'maybe seenv that this trimdiffers from the previous 'peripheral trim only-in omitting .thetransversely extending wall |08. 'The upper portion of the trim 32hoverlies the edge of the outer wall 2|6 to hide the joint between it andthe ground 46. The same is of course true of the joint along thevertical grounds 52 and 54. In this particular illustration, a shelftype of chalk trough is provided which is identical with the troughshown in Figure 9 and is numbered 34h in this figure. The lower portionof the chalk trough as well as the lower portion of the mounting clips32 overlies the joint between the outer wall 2|6 and the ground 50 tohide the same.

A modification of the recessed mounting is shown in Figures 13 and 14 toillustrate another of the constructional features of my invention. Thewall 36, outer wall 2 I 6, ground 46, springs 64, and blackboard 3U areidentical with those shown in Figure 12. A map rail 209 having a channelshaped body portion with inturned flanges 2| I is secured to the ground46 by means such as screws 2| 3. The back of the map rail is not fiat,but has its longitudinal edges 215 turned slightly backward to form asharp edge which bites firmly against the wall to make a dust tightjoint. It is to be understood that any of the trim or the chalk troughcould be formed with such edges and this construction is not to belimited to a map rail.

In Figure 15 is illustrated an inclined closed type chalk trough 2|8usable with a fiush or recessed type mounting. The outer wall 2I6, theground 5D, mounting springs 64, mounting clips 82, and the blackboard3D, as well as the supporting wall 36, may be the same as those shown inFigure 12. The chalk trough 2 I 8 is similar to the inclined closed typeof chalk trough shown in Figure 7 having an inclined undulating top orfront surface |160 terminating at its upper extremity in a feather edge|800 and folded over at its lower margin to form a cylindrical edge |840merging into a smoothly curved wall I B60 terminating in an upstandingflange or wall |900. There is no portion akin to the horizontal wall |88in the configuration shown in Figure 7, as the longitudinal upstandingwall |9|lc is flush against the outer wall 2|6. As in the earliermodification, the chalk trough 2|8 is provided with a longitudinalrecess |180 along its rear face directly below the feather edge |80c,and a longitudinal ange or wall |820 depends from just below thisrecess. The mounting and securing of this modification is similar tothat of previous illustrations with the flange |820 behind the clipflange S2 and the wall or flange |900 behind the camming surface 96. Anend plate 220 for the chalk trough 2 I8 is shown in Figures 16 and 17.The cross section of the end plate is such as to conform to the crosssection of the chalk trough 2|8 and the upper surface is relieved as at222 to facilitate the sweeping of chalk dust from the trough. Inwardlyextending nanges 224 and 226 nest within the chalk trough 2|8 and theend plate to secure it in place by means such as screws 228 threadedinto these flanges.

The construction described in each of the foregoing modifications inwhich a metal ground is utilized is greatly to be preferred as suchinstallation is reproof, vermin-proof and relatively permanent. In somecases, however, usually in order to save on initial costs, it isdesirable to utilize wooden grounds rather than metal ones. In suchcases it is possible to use my mounting structure with no modificationother than the drilling of a few holes, which is readily accomplishedwith the extruded aluminum from which iii* my trim and chalk trough arepreferably made. In Figures 22 through 26, a modification of myinvention using wooden grounds is illustrated. The wall 36 may beidentical with that shown previously. Wooden grounds 46d, 43d, 56d, 52dand 54d extending out as far as the surface of the blackboard may beused with wooden spacer strips 23|] mounted along the front surface ofeach one. It is not necessary to use such twopiece construction,although only one width of ground need then be supplied, as generallythe spacer strip and ground, as for instance 23B and 46d, are mounted incontiguous relation against the wall 36 by means such as nails 232.Peripheral trim 32d along the top and sides of the structure isidentical with the trim 32 used in conjunction with the metal groundsexcept for spaced apertures through which mounting screws 234 arethreaded. into the wooden grounds to secure the trim. The inner edge ofthe trim overlies the various slabs of the blackboards 30a, 30h in thesame manner as with the metal grounds. In the same manner the mulliontrim 31d is identical with thetrim 31 except for the spaced aperturesthrough which mounting screws 236 are threaded into the wooden ground48d. Likewise, the shelf type chalk trough 34d is identical with thetrough 34 illustrated in Figure i with the addition of spaced aperturesthrough which mounting screws 238 are threaded into the ground 52d. Amap rail 42d shown in Figure 2S may be identical with that shown inFigure 5 since mounting screws were used there to secure a map rail inplace. In this instance, a tack board 38d having a backing |26d is shownsecured beneath one longitudinal edge of the map rail 42d, and ablackboard 30d is secured beneath the other longitudinal edge. In thisi1- lustration the ground is used without the spacer strip 230 as theback surface of the map rail is flush with both the display board andthe ground rail. This illustrates the desirability of having a ground ofthis size, which in other instances may be built up by the spacer strips23D rather than supplying grounds of different sizes. The rail is ofcourse secured to the ground by several fasteners such as the screws|32d. Inasmuch as the wooden grounds have no anges on which to mountsprings, I have found it desirable to mount at least two rows of springsbeneath each panel or slab of a display board in order to secure thefloating mounting desired. The blocks '16d securing the springs 64d maybe identical with those previously described without the suffixes andare placed near the periphery of each slab, as shown in Figure 24.

If it is not desired to drill holes in the trim and chalk trough andhave the mounting screws showing, it is possible to mount the trim andchalk trough by means of the clips previously described even whenutilizing wooden grounds, as may clearly be seen in Figures 25 and 26.The wall 36, wooden ground 46d and blackboard 30a may all be identicalwith those shown in Figure 22 and the clip 82 and trim 32 may beidentical with those shown in Figure 4. A single nail, which may be oneof the ground mounting nails 232, may be used to mount each clip,although in the case of the chalk trough mounting clips it may bedesirable to use two such nails. The inturned end lugs 98 of the clip 82may be driven readily into the wooden ground 46d by any drivingimplement such as a hammer to aid in securing the clips in properposition.

It is .apparent :that .1I have `shown herein van improved typeofmountingstructure forsecuring .blackboardsz and '.theiike in :floatingposition, the structure being ,usable with either vmetal or woodengrounds and being-readily adapted to a recessed type :mounting :although.being particualarly designed for amounting in which Ythe Yen- '.tire`structure extends :from the plane of ythe wall.

Although I have shown and described certain .preferred`- embodiments :of:my ,invention for purposesof illustration, vit is tovbe understood that.I doznot intend myiinvention to Vbe limited `thereby' and that itshould 'be construedto include all that -wliich may fairly fall withinthespirit vand 4scope :of fthe: appended claims.

`1. A-.securingmember for use in displayboard construction -.compr,isinga substantially -fl-at Lplate-likebodyportion, a flange along onelongitudinal edge, .a shoulder between-said bodypor- .tion and saidflange, a vcam surface Aalong the other longitudinal'edge, anda-.shoulder'between said'body portion andsaid cam surface.

2. The combination for use in display `board vrconstruction comprising.an -elongated strip including .a longitudinally -recessed .front face,'and a securing :member .including a substantially flat plate-like bod-yportion, trim vsupporting structure on said securing member, and anextending ,projectiononsaid-body portion cooperating with .therecess 3.A .building .construction for supporting fa .display board -or the likeon .a wall comprising a pluralityofground strips ,mounted on andvextending .outwardly from `said wall.. and :forming a framework,elongated, ornamental. trim comprising `a front wall, .anarrowsidewallextending .from one edgeofsaidfront wall, arelatively .wide

side wall extending from .the opposite ,edgefofisaid jfront wall, anda,plurality of .flanges vextending from saidside 4walls substantiallyparallel to `said front wall, and Ymeans mounted lon .said ground strips-for engaging said Yiianges to secure said trim on saidgroundstrips tocover .the.latter.

4. A building construction for `supporting a displayboard or .the likeona wall comprisinga plurality of ground strips forming aframework,vsecuring means on said ground strips, .ornamental trim secured by someof said securing means Yand covering some .of said Vground strips, and achalk trough secured b y the remainder of said securing means and1covering the remainder of said ground strips, said chalk troughincluding a chalk supporting tray and a rear wall having an upperIlongitudinal -edge engageable with ,a display board, said rear wall'having a rear 'face longitudinally recessed immediately below saidlongitudinal edge to A'impart flexibility to the upper'portion of saidchalktrough.

5. A building Vconstruction for supporting a display board-or the `likeon la Wall comprising a :ground construction forming a framework havinga front surface and comprising a plurality of elongated strips arrangedon the surface `of a iwall andextending therefrom, a plurality ofsecuring members on said strips, a plurality of trim members Asecuredover said .securing members vand-,covering some of `said strips and saidsecuring members, and a-.chalk trough -securable over the remainderof-saidfsecuring members and covering the remainder of said .elongatedstrips, said .chalk trough including -an V`upper longitudinal edge forbea-ring against .la display board in mounted position and a vlowerlongitudinal wall i2 vertically .displaced from lsaid longitudinal :edgeyand .extending rearwardly 'beyond said display .board and said edge andabutting said-wall tto underlie and cover Vthe remainder of .said-groundstrips.

6. In display boardrmounting construction van elongated ground strip, aplurality ofrigid'securfing memberson said ground strip, eachof saidsecuringmembers including a rigid ange along one longitudinal edge and4a .rigid vcam surface along the other `longitudinal edge, and a chalk:trough securable over said securing members, ,said'chalk troughcomprising an eraser support- Aingwall, a flange integral with saideraser supporting wall and engageable'over the rigid 4longitudinalflanges of said securing members, a`lower rsubstantially horizontal wallvertically displaced v'from said eraser supporting -wall and underlyingvsaid securing members, a iiange on said .lower .wall ,cooperable withthe rigidcam surfaces of -said securing members tomount and secure saidchalk trough, an upwardly directed extension integral with said wallhaving an inclined surface above said eraser supporting wall, and arearsurface recessed toineetsaid inclined surf-aceiat ra sharp acute Yangleto provide a feather ledge' for `sealing vsaid'chalk trough tozablackboard-and to Yfacilitate .installation .of said chalk ztrough.

7. The combination for use in a Ydisplay board .construction comprisingan elongated striphaving a longitudinally recessed front face, and a se-`curing member including a substantially .fiat ,plate-like 'body:,portion, a plurality -of tongues integral vwith said body portion and.extending ktherefrom -into said recess, and'means for retaining saidsecuring member Von the front Afaceof said strip with .said.plurality-of tongues insaid recess.

v8. ,A .display .board construction comprising va display board, asupporting wall, a plurality `of ground Ystripsmounted on said wall.anddening a wallarea, saidground strips attheir .peripherallongitudinal edges meetingsaid supporting wall `at substantially .aright angleandhaving .fianges extending into vsaid wall area, a.plurality of springs, certain of said springs being mounted on theiianges of said Aground .strips,.the.remaind er .of said springsbeingmounted on members within said wall `area to Vlie in a-common planewith springs on said ground strip and .spaced fromsaid ground strips asubstantial distance, and securing means mounted on said .ground stripssubstantially ina second commonplane, saidsprings tending toextendforwardly toward said secondcommon plane to assume a positionspaced from said second common plane less than thethickness of saiddisplay board, thesecuring means overlying and clamping saiddisplay'board against 'said springs.

9. A ground strip for use with a clip having spaced ground strip.engaging projections and trim engaging'portions, comprising anelongated member having a wall surface, a pair of side surfacestransverse to said wall surface and arear surface contiguous with atleast one of said side surfaces and-generally parallel to andtransversely opposite from said wall surface, said wall surface havinga'channel-like recess extending substantially the entire length thereoffor cooperationwiththe spaced ground strip engaging projections on vtheclip, the spaced projections and Ythe channel-'like recess in the groundstrip cooprating Vto prevent .rotation of the clip with respect -.to4the Vground strip in the plane of the 10. A trim for use with a displayboard positioned outwardly with respect to a support structure havingtrim engaging means thereon, comprising a front Wall to overlie thefront face of the display board, a relatively narrow side wall extendingtransversely from one edge of said front wall and toward the front faceof the associated display board, a relatively wide side wall extendingfrom the opposite edge of said front wall and in the same direction assaid narrow wall to overlie and cover the free edge of the associateddisplay board and the space between the display board and its supportingstructure, and a ilange formed on each of said side walls and extendingtoward the other side wall for engagement with the trim engaging means.

1l. The combination for use in a display board construction comprisingan elongated ground strip, a clip mounted on said ground strip, saidclip including a substantially fiat plate-like body portion, trimengaging means formed on said body portion and extending outwardlytherefrom, and a plurality of projections formed on said body portionand extending in a direction opposite to said trim engaging means andtoward said strip, said strip having cooperating means formed thereon toreceive said projections, said projections and cooperating meanspreventing rotation of said body portion with respect to said strip inthe plane of said body portion.

12. A chalk trough for use with a display board having a trough engagingclip mounted adjacent thereto, comprising a chalk supporting member, afirst flange extending from said chalk suplporting member and toward thedisplay board in mounted position, said first ange having a longitudinaledge for bearing against the disiplay board to form a tight juncturetherewith, a second flange formed on said chalk supporting member anddirected away from and downwardly with respect to said rst flange inmounted position, said second iiange having means formed thereon toengage the clip, a third flange formed on said chalk supporting memberand extending upwardly from below said second ange when the chalk troughis in mounted position, said third flange having means formed thereon toengage the clip.

13. A chalk trough as set forth in claim 12, wherein the third ange isattached to the chalk supporting member at the edge thereof opposite thepoint of attachment of the first flange.

14. A chalk trough as set forth in claim 12, wherein the display boardis spaced outwardly from the adjoining support wall and the third flangehas an extension thereon underlying and covering the space between thefront of the display board and the surrounding supporting wall.

LEON F. URBAIN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,991,882 Dill Feb. 19, 1935 2,135,982 Masters Nov. 8, 19382,300,248 Elnett Oct. 27, 1942 2,319,278 Urbain May 18, 1943

